Devices and methods for delivery of desired components to a site of interest remain a growing need. For example, a variety of methods and routes of administration have been developed to deliver pharmaceuticals, such as small molecular drugs and other biologically active compounds (e.g., peptides, hormones, proteins, and enzymes). Many routes of administration are known for delivering desired pharmaceuticals to a patient. As greater knowledge is learned regarding toxicity of drugs and the ability to elicit specific responses by delivery of a pharmaceutical only to a specific portion of the body, controlled release of pharmaceuticals after their administration has become a highly important area of research.
Gene therapy, for example, is a promising field; however, such therapy requires gene or polynucleotide transfer across the cell membrane and into the nucleus where the gene can be expressed. Many conventional drug delivery techniques simply cannot provide a delivery vehicle of sub-cellular dimensions that can effectively deliver specific materials to individual cells. The effectiveness of drugs and other compounds can also be increased by target specific delivery, and the use of micro- or nano-sized delivery devices can be particularly beneficial to increase drug activity while actually reducing the overall concentration of drug delivered. Accordingly, there is a need in the art for compounds and methods useful to facilitate delivery and release of desired compounds to a site of interest, particularly on a micro- or nano-size scale.